OLEDs polarized light

In addition, the chiral conformation suggests that poly(DBF) and its family may find applications in the fields such chiral recognition, nonlinear optical materials, and chiral catalysis. An application based on the combination of chirality and charge transport is circularly polarized light for OLEDs. 

Very recently there has been a report about bridged triarylamine helicenes exhibiting CPL [131], These molecules preferentially emit and absorb CP light without the help of an LC matrix. Currently, there seems to be ongoing work to further increase the efficiency of these types of CPL materials and to develop first devices of polarized OLEDs. 

Light-emitting electrochemical cells, and OLEDs, 12, 175 Light-emitting molecules, by G-H bond activation, 10, 244 Light propagation, and second-order non-linear polarization, 12, 104... 

Biaxially oriented films such as PET and PEN are birefringent. For LC displays which depend on light of known polarization this means that birefringent films, which would change the polarization state, are unlikely to be used as substrates. Films based on amorphous polymer are not birefringent and are more suitable for LC displays. Birefringence is not an issue with OLED, electrophoretic displays, or, indeed, some LC displays. 

OLED display manufacturers have so far used circular polarizers borrowed from the LCD technology to improve contrast (Trapani et al, 2003). This approach does not require introduction of new layers in the OLED structure and results in reflectance similar to that of glass. However, polarizers are expensive, generally not flexible, and absorb a substantial amount of the light (up to 40%) (Wu, 2005). 

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